Fix verify_tag build stage in Travis pipeline

.travis.yml

@@ -14,7 +14,7 @@ jobs:
   - stage: verify-tag
     python: 3.7
     script: >
-      [ "v$(python -c 'import kubernetes ; print(kubernetes.__version__)')" == "${TRAVIS_TAG}" ] &&
+      [ "v$(python -c 'from scripts.constants import CLIENT_VERSION; print(CLIENT_VERSION)')" == "${TRAVIS_TAG}" ] &&
       [[ "${TRAVIS_TAG}" =~ ^v[0-9]+\.[0-9]+\.[0-9]+(([ab]|dev|rc)[0-9]+)?$ ]]
   - stage: test
     python: 2.7